Low on memory messages playing Skyrim with 4GB
I use Windows 7 Ultimate 64 bit and have 4 gb of ram installed ( 2 sticks of Kingston Hyper X DDR2). I can run most programs just fine without any problems, like Maxed Far Cry 2 and Deus Ex: HR. However, whenever I play Skyrim (on High/Ultra, but i haven't tested the other settings) I get messages of low memory usages.
I'm pretty sure this doesn't mean that Skyrim is taking up so much RAM that I need more than 4 GB because I know people have ran it on maxed setting with 4 GB just fine (and on top of that I'm assuming Skyrim doesn't really need THAT much more ram than programs like Crysis or Far Cry 2). I use CCleaner from time to time but haven't used it lately, nor have I defragged in a while. Are these the reasons why this is happening, or is it more likely that there's something wrong with my sticks? What should I do to make sure?
Thanks In advance.